Constrictive Pericarditis 

The thousand mysteries around us would not trouble but interest us, if only we had cheerful, healthy hearts.

–Nietzche

If we all had healthy hearts, the mysteries of the heart would not trouble us; however, constrictive pericarditis certainly has been a mystery and remains a diagnostic challenge to this day.

The history of constrictive pericarditis is replete with some of the most famous names in medicine. Richard Lower described a patient with dyspnea and an intermittent pulse in 1669. Lancisi first reported on the constrictive syndrome in 1828. Corrigan described the pericardial knock in 1842. Kussmaul described his sign and the associated paradoxical pulse in 1873.^{[1, 2, 3]}

Constrictive pericarditis has symptoms that overlap a variety of diseases as diverse as myocardial infarction, aortic dissection, pneumonia, influenza, and connective tissue disorders. This overlap can confuse the most skilled diagnostician. An increased suspicion for constriction helps move it to the top of the broad differential diagnosis and provides for a correct diagnosis and timely therapy.

Constrictive pericarditis occurs when a thickened fibrotic pericardium, of whatever cause, impedes normal diastolic filling. This usually involves the parietal pericardium, although it can involve the visceral pericardium (see Pericarditis, Constrictive-Effusive). Acute and subacute forms of pericarditis (which may or may not be symptomatic) may deposit fibrin, which may, in turn, evoke a pericardial effusion. This often leads to pericardial organization, chronic fibrotic scarring, calcification, and restricted cardiac filling.^[4]

The classic diagnostic conundrum of constrictive pericarditis is the difficulty in distinguishing it from restrictive cardiomyopathy (see Cardiomyopathy, Restrictive) and other syndromes associated with elevated right-sided pressures that all share similar symptoms, physical findings, and hemodynamics. Although obtaining a careful history and performing a physical examination remain the cornerstones of evaluation, technologic advances have facilitated diagnosis, particularly with the appropriate use of Doppler echocardiography, high-resolution computed tomography (CT), magnetic resonance imaging (MRI), and invasive hemodynamic measurement.

The normal pericardium is composed of 2 layers: the tough fibrous parietal pericardium and the smooth visceral pericardium. Usually, approximately 50 mL of fluid (plasma ultrafiltrate) is present in the intrapericardial space to minimize friction during cardiac motion.^[5]

Acute and subacute forms of pericarditis (which may or may not be symptomatic) may deposit fibrin, which may, in turn, evoke a pericardial effusion. This often leads to pericardial organization, chronic fibrotic scarring, and calcification, most often involving the parietal pericardium (see Pericarditis, Constrictive-Effusive).^[6]

This thickened fibrotic pericardium, regardless of cause, impedes normal late diastolic filling, distinguishing constrictive from restrictive pericarditis. Since the myocardium is unaffected, early ventricular filling during the first third of diastole is unimpeded, but afterwards, the stiff pericardium affects flow and hemodynamics. In other words, the ventricular pressure decreases rapidly early (producing a steep y descent on right atrial pressure waveform tracings) and then increases abruptly to a level that is sustained until systole ("dip-and-plateau waveform" or "square root sign" seen on right or left ventricular pressure waveform tracings).^[7]

The clinical symptoms and classic hemodynamic findings can be explained by early rapid diastolic filling and elevation and equalization of the diastolic pressures in all of the cardiac chambers restricting late diastolic filling, leading to venous engorgement and decreased cardiac output, all secondary to a confining pericardium.

Frequency

United States

Similar to many diseases that in the past were predominantly infectious in origin, the clinical spectrum of constrictive pericarditis has changed in recent years. Approximately 9% of patients with acute pericarditis for any reason go on to develop constrictive physiology.^[8] T he true frequency is therefore dependent on the incidence of the specific causes of pericarditis, but since acute pericarditis is only clinically diagnosed in 1 in 1,000 hospital admissions, the frequency of a diagnosis of constrictive pericarditis is less than 1 in 10,000 hospital admissions.

International

In the developing world, infectious etiologies remain more prominent (tuberculosis has the highest total incidence).

Mortality/Morbidity

• Scant data exist because the disease is rare.
• The underlying disease usually determines the prognosis. Poorer prognoses are associated with malignancy and New York Heart Association (NYHA) class III or IV heart failure symptoms.
• Long-term survival after pericardiectomy depends on the underlying cause. Of common causes, idiopathic constrictive pericarditis has the best prognosis (88% survival at 7 years), followed by constriction due to cardiac surgery (66% at 7 years). The worst postpericardiectomy prognosis occurs in postradiation constrictive pericarditis (27% survival at 7 years). This likely represents confounding comorbidities. Predictors of poor outcomes in patients who undergo pericardiectomy including history of prior radiation, worsening renal function, pulmonary hypertension, systolic heart failure, hyponatremia, and advanced age.^{[9, 10]}

Race

• No race predilection exists for this disorder.

Sex

• Most likely a male predominance exists, with a male-to-female ratio of 3:1 in some studies.

Age

• Cases have been reported in persons aged 8-70 years. Predilection is likely reflective of the underlying disease.
• Historical studies suggest a median age of 45 years, while more recent studies suggest a median age of 61 years. This likely reflects a demographic change that is likely to continue.